US3962969A - Ink mist type high speed printer - Google Patents

Ink mist type high speed printer Download PDF

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Publication number
US3962969A
US3962969A US05526387 US52638774A US3962969A US 3962969 A US3962969 A US 3962969A US 05526387 US05526387 US 05526387 US 52638774 A US52638774 A US 52638774A US 3962969 A US3962969 A US 3962969A
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US
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Grant
Patent type
Prior art keywords
board
aperture
ink mist
aperture board
apertures
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05526387
Inventor
Akinori Watanabe
Katsuhide Tanoshima
Matsusaburo Noguchi
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Oki Electric Industry Co Ltd
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Oki Electric Industry Co Ltd
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Filing date
Publication date
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/215Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material by passing a medium, e.g. consisting of an air or particle stream, through an ink mist
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00Printing
    • Y10S101/37Printing employing electrostatic force

Abstract

A conductive protection board for protecting an aperture board from dust is mounted in an ink mist type high speed printer. The ink mist type printer operates on the principle that an ion stream modulated by an aperture board according to the pattern of the character to be printed, charges the ink mist, which is then attracted by an electric field to the surface of the paper. If an aperture of said aperture board is obstructed, a portion of the printed character will not be evident. In order to avoid the obstruction of an aperture the conductive protection board which has a plurality of apertures, each of which corresponds to each aperture of the aperture board, is placed very close to said aperture board.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an ink mist type high speed printer.

The operational speed of an information processing system including a computer system has recently been improved, thus requiring the use of a high speed peripheral device including a printer. A conventional high speed printer is a line printer with a type drum or a type train. However, this line printer has many disadvantages, some of which are that the operational speed is not sufficient for the latest information processing system, and the process involves a high level of noise and/or limitation of the number of printing types. In order to overcome these disadvantages of the prior line printer, some high speed printers with new operational principles have been developed. Among them, one of the most promising is an ink mist printer. The ink mist type printer operates at high speed, i.e. 8,000 lines per minute, with a low sound noise level. Further, it can type not only alphanumeric characters but also Chinese or Japanese characters.

The operational principle of an ink mist type printer is that an ion stream generated by corona discharge passes through apertures of an aperture board and ionizes an ink mist, and the movement of the electrically charged ink mist is accelerated by a negative electrode and is attached to paper according to the pattern of characters.

The disadvantage of the prior ink mist type printer was that dust obstructs apertures in the aperture board and prevents the passage of the ions. The obstructed apertures create incompletely printed characters and the source of the trouble cannot be located until the printing operation is actually completed, therefore wasting both paper and operational time.

Further, the dust created on the edges and/or perfurated holes of paper is apt to obstruct the abovementioned apertures.

SUMMARY OF THE INVENTION

The general purpose of the present invention is to provide an improved ink mist type printer with a facility for eliminating the obstruction of apertures by dust.

It is an object, therefore, of the present invention to overcome the disadvantages of the prior ink mist type printer by providing a protection board in an ink mist type printer. According to the present invention, a conductive protection board which has a plurality of apertures, each of which corresponds to each aperture of the aperture board, is inserted between the aperture board and the paper, very close to said aperture board, in order to prevent the dust from obstructing apertures in the aperture board.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and attendant advantages of the present invention will be appreciated as they become better understood by references to the accompanying drawings wherein.

FIG. 1 shows (the explanatory) sectional view of a conventional ink mist type printer;

FIG. 2 shows a sectional view of an ink mist generator in the conventional ink mist type printer;

FIG. 3 shows a perspective view of a conventional aperture board;

FIG. 4 shows a sectional view of an ink mist type printer according to the present invention;

FIG. 5 and FIG. 6 are enlarged views of a protection board 12 in FIG. 4; and

FIG. 7 shows a brief circuit diagram concerning a protection board according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, the operational principle of an ink mist type printer will be explained to provide a basis for understanding of the present invention.

FIG. 1 shows a basic structure of a prior ink mist type printer. The principle of typing in an ink mist type printer is to attach an ion stream to an ink mist which types or draws characters on printing medium such as a sheet of paper. Said ion stream is controlled by an electric field on an aperture board according to the pattern or shape of printed characters. In FIG. 1 an aperture board 5 is positioned between a positive electrode 4 and printing medium 1. The printing medium 1 is just ordinary paper. A negative electrode 3 is provided behind the printing medium 1 and doubles as a platen. The positive electrode 4 is a thin straight line made of tungsten. Several thousand volts applied to the positive electrode 4 generates a corona discharge and an ion stream 13.

The strength of the electrical field required for corona discharge depends upon the shape of the positive electrode 4 and is generally 1000 - 1300 V/mm. The movement of the ion stream 13 generated on the positive electrode 4 is accelerated by the negative electrode 3 and passes through apertures 5d of the aperture board 5, the structure of which is shown in detail in FIG. 3, wherein reference number 5c is a dielectric layer, and 5a and 5b are conductive layers. The conductive layer 5a is separated into a plurality of cells shown as a, b, c, d, . . . . . , and each cell a, b, c, . . . . . is insulated from the others. On the other hand the conductive layer 5b is common to all cells a, b, c, ............... . A voltage E is applied to each cell of the conductive layers 5a and 5b, and the distribution of voltage E is related to the pattern or shape of the character to be printed. An electric field generated in the aperture by said voltage E prevents or accelerates the passage of the ion stream according to the polarity of the voltage E, therefore, the density of the ion stream which comes out of the aperture board 5 is modulated according to the pattern of the character. Voltage E is supplied by a character generator (not shown).

There is an ink mist between the aperture board 5 and printing medium 1. The ion stream 13 modulated by the aperture 5 attacks and charges the particles of the ink mist, then, the charged particles 7b of the ink mist are accelerated by the negative electrode 3 and attached to the surface of the printing medium 1. Thus, the pattern of the character is printed on the printing medium in ink.

FIG. 2 shows the structure of an ink mist generator, which comprises an ink tank 6 containing ink 7, an ink inlet 6a, an ink outlet 6b, and ultrasonic wave exciters 8. The depth of the ink 7 in the ink tank 6 is maintained automatically at a desirable depth by the ink stream through the inlet 6a and the outlet 6b. The exciters 8 generate ultrasonic waves and generate ink mist 7a, the diameter of which is 5 - 20 μ. The ink mist 7a is transported by an air stream 15 to an ink guide 14 (FIG. 1), and directed along arrow Y in the same direction as the movement of the paper 1. The moving speed of the ink mist 7a is almost the same as that of the paper 1. The ink mist which is not used for printing is gathered and condensed in a tank (not shown).

One problem of a conventional ink mist type printer is, as explained before, that apertures of the aperture board are sometimes obstructed by the dust forming on paper 1, thus obscuring portions of the printed character.

FIG. 4 is a simplified view showing the sectional view of the main printing part of the ink mist type high speed printer, according to the present invention. In FIG. 4 numeral number 1 indicates a recording paper running in the direction indicated by an arrow X, numeral 2 is a platen disposed on the back of the recording paper 1 and installed with a negative electrode 3, numeral 4 is a positive electrode composed of a thin wire made of tungsten, numeral 5 is an aperture board including a selection electrode 5a, a common electrode 5b and an insulating member 5c interposed between the two electrodes and having a plurality of penetrating apertures 5d aligned in the lengthwise direction thereof, numeral 6 is a mist tank for vibrating and atomizing an ink solution 7 by applying an electric pulse to an ultrasonic exciter 8 composed of a piezo-electric material, numeral 9 is a main pump for feeding air to the mist tank 6, numeral 10 is a condenser for separating the ink from air recovered from the printing zone, and numeral 11 is a cooler. Numeral 12 denotes an electrically conductive protection board disposed close to the aperture board 5 as shown in FIG. 5 and FIG. 6. A plurality of apertures 12a, 12b, . . . . . are perforated through the electrically conductive protection board 12 at positions corresponding to ion-passing apertures of the aperture board 5. In order to facilitate passage of ions through these apertures 12a, 12b, . . . . . , it is necessary to apply a voltage adjusted appropriately depending on the position at which the electrically conductive protection board 12 is disposed. Ions for causing ink particles to stick on the recording paper 1 are modulated by the aperture board 5. More specifically, movement of the ions is prevented or accelerated depending on the polarity of the selection electrode 5a of the aperture board, namely whether the selection electrode 5a is positive or negative to the common electrode 5b.

Since the surface of the recording paper 1 is readily electrostatically charged, various dust particles differing in the size are likely to accumulate thereon. This dust falls on the aperture board 5 from the recording paper 1 due to laminar flows of air in the printing zone. Further, when the recording paper 1 is broken or movement of the recording paper 1 is interrupted during the printing operation, the ink adheres on one particular portion of the platen 2 or recording paper 1, so that the ink is accumulated in a mountain-like form at said portion and falls upon the aperture board 5 due to its own weight.

In the apparatus of this invention, since the electrically conductive protection board 12 is disposed above the aperture board 5, dusts and ink are collected on said protection board 12 and they are prevented from reaching the aperture board. Accordingly, the aperture board 5 can be kept continuously free of dust merely by cleaning the electrically conductive protection board 12 at an appropriate time or replacing it by a fresh protection board. As a result, in the apparatus of this invention, inhibition of the movement of ions by jamming of penetrating apertures 5d of the aperture board 5 can be effectively prevented.

The aperture board 5 is actually composed of a thin dielectric sheet and printed conductive layers (selection electrode 5a and common electrode 5b).

FIG. 7 shows a brief circuit diagram concerning a conductive protection board 12. In FIG. 7, the same reference numbers refer to the same members as those of FIG. 4. A conductive protection board 12 is inserted between the aperture board 5 and the paper 1, close to said aperture board 5. Each aperture of the aperture board 5 corresponds to each aperture of the conductive protection board 12, therefore, an ion stream generated by the positive electrode 4 can pass through the aperture 5d of the aperture board 5 and the aperture 12a of the conductive protection board 12. The conductive protection board 12 is connected electrically to the Direct Current source 16 and supplied with the desired voltage. On the other hand, each cell of the separated conductive layer 5a is connected to an output of a drive circuit 17, the input of which is connected to the output of a selection circuit 18. The selection circuit 18 selects the cells to which high voltage E1 is applied according to the pattern to be printed. Since there are a plurality of cells on the layer 5a, a plurality of drive circuits 17, must be provided. However, only one representative drive circuit 17 is shown. The common layer 5b is electrically connected to the other D.C. source 16a.

As is apparent from the above explanation, an improved ink mist type high speed printer which prevents the obstruction of the apertures of the aperture board and thus facililates the maintenance of the printer.

Another effect of the present invention is that there is a reduction in the wastage of printing paper.

It can be seen that the present invention provides a simple and unique ink mist type printer and although it has been described with respect to embodiments, it need not be so limited, as changes and modifications may be made which would fall within the scope of the invention as defined by the appendant claims.

Finally, reference numbers used in this specification are listed below.

______________________________________1;   printing medium               2;    platen3;   negative electrode               4;    positive electrode5;   aperture board               6;    mist tank7;   ink            8;    exciter9;   main pump     10;    condenser11;  cooler        12;    conductive protection board13;  ion stream    14;    ink guide15;  air stream    16;    D.C. source17;  drive circuit 18;    selection circuit______________________________________

Claims (3)

What is claimed:
1. In an ink mist type printer for use in printing information on a printing medium, which printer includes means for generating an ion stream comprising a pair of spaced upper and lower electrodes to which a high voltage is applied, means positioned between said electrodes for modulating said ion stream including an electrically controlled aperture board having a plurality of apertures therein, said apertures being positioned in at least one aligned row through which the ion stream passes and is modulated, means for supplying an ink mist between the aperture board and the upper of said electrodes whereby the modulated ion stream charges the mist according to the pattern to be printed on a printing medium arranged parallel to the flow of said ink mist and between said upper electrode and the aperture board whereby characters are printed on said medium by the attraction to said upper electrode of the charged ink mist; the improvement which comprises a conductive dust protection board positioned above said aperture board and below said printing medium, said protection board having a plurality of apertures formed therein corresponding to and located in alignment with said apertures of said aperture board, thereby to prevent dust particles from falling downwardly from the printing medium onto said aperture board.
2. An ink mist type printer according to claim 1, wherein the upper surface of the aperture board is curved and said conductive protection board has a complementary curve.
3. An ink mist type printer according to Claim 1 including means for applying D.C. voltage to said conductive protection board.
US05526387 1973-12-03 1974-11-22 Ink mist type high speed printer Expired - Lifetime US3962969A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JA48-134408 1973-12-03
JP13440873A JPS5413974B2 (en) 1973-12-03 1973-12-03

Publications (1)

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US3962969A true US3962969A (en) 1976-06-15

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US05526387 Expired - Lifetime US3962969A (en) 1973-12-03 1974-11-22 Ink mist type high speed printer

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US (1) US3962969A (en)
JP (1) JPS5413974B2 (en)
DE (1) DE2456597B2 (en)
FR (1) FR2252924B1 (en)
GB (1) GB1455674A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4314258A (en) * 1980-02-04 1982-02-02 The Mead Corporation Ink jet printer including external deflection field
US4338614A (en) * 1979-10-22 1982-07-06 Markem Corporation Electrostatic print head
US5229794A (en) * 1990-10-04 1993-07-20 Brother Kogyo Kabushiki Kaisha Control electrode for passing toner to obtain improved contrast in an image recording apparatus
US5231427A (en) * 1991-09-20 1993-07-27 Brother Kogyo Kabushiki Kaisha Image recording apparatus
US5257045A (en) * 1992-05-26 1993-10-26 Xerox Corporation Ionographic printing with a focused ion stream
US5752142A (en) * 1993-10-13 1998-05-12 Watermark Imaging Ltd. Method and apparatus for developing electrostatic images
US20020180854A1 (en) * 2001-03-28 2002-12-05 Canon Kabushiki Kaisha Process for forming image with liquid droplets, image forming apparatus utilizing such process and process for ejecting and projecting liquid droplets

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5525066B2 (en) * 1974-10-30 1980-07-03
JPS5412341B2 (en) * 1974-10-30 1979-05-22
DE2750875A1 (en) * 1976-11-16 1978-05-24 Vital Zoltan Dr combined machine

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577894A (en) * 1948-01-16 1951-12-11 Carlyle W Jacob Electronic signal recording system and apparatus
US2676868A (en) * 1952-06-10 1954-04-27 Carlyle W Jacob Electronic signal controlled recording system and apparatus
US3177800A (en) * 1962-06-28 1965-04-13 Sperry Rand Corp Immersed spark gap printer
US3273496A (en) * 1964-08-28 1966-09-20 Crocker Citizens Nat Bank Powder feed for electrostatic printing system with an electric field free chamber
US3653065A (en) * 1969-10-22 1972-03-28 Clevite Corp Electrographic recording system with interleaved electrode groups
US3769627A (en) * 1972-12-13 1973-10-30 Dick Co Ab Ink jet printing system using ion charging of droplets
US3779166A (en) * 1970-12-28 1973-12-18 Electroprint Inc Electrostatic printing system and method using ions and toner particles
US3832719A (en) * 1972-04-21 1974-08-27 Ibm Modified diffused ink jet printer

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577894A (en) * 1948-01-16 1951-12-11 Carlyle W Jacob Electronic signal recording system and apparatus
US2676868A (en) * 1952-06-10 1954-04-27 Carlyle W Jacob Electronic signal controlled recording system and apparatus
US3177800A (en) * 1962-06-28 1965-04-13 Sperry Rand Corp Immersed spark gap printer
US3273496A (en) * 1964-08-28 1966-09-20 Crocker Citizens Nat Bank Powder feed for electrostatic printing system with an electric field free chamber
US3653065A (en) * 1969-10-22 1972-03-28 Clevite Corp Electrographic recording system with interleaved electrode groups
US3779166A (en) * 1970-12-28 1973-12-18 Electroprint Inc Electrostatic printing system and method using ions and toner particles
US3832719A (en) * 1972-04-21 1974-08-27 Ibm Modified diffused ink jet printer
US3769627A (en) * 1972-12-13 1973-10-30 Dick Co Ab Ink jet printing system using ion charging of droplets

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4338614A (en) * 1979-10-22 1982-07-06 Markem Corporation Electrostatic print head
US4314258A (en) * 1980-02-04 1982-02-02 The Mead Corporation Ink jet printer including external deflection field
US5229794A (en) * 1990-10-04 1993-07-20 Brother Kogyo Kabushiki Kaisha Control electrode for passing toner to obtain improved contrast in an image recording apparatus
US5231427A (en) * 1991-09-20 1993-07-27 Brother Kogyo Kabushiki Kaisha Image recording apparatus
US5257045A (en) * 1992-05-26 1993-10-26 Xerox Corporation Ionographic printing with a focused ion stream
US5752142A (en) * 1993-10-13 1998-05-12 Watermark Imaging Ltd. Method and apparatus for developing electrostatic images
US20020180854A1 (en) * 2001-03-28 2002-12-05 Canon Kabushiki Kaisha Process for forming image with liquid droplets, image forming apparatus utilizing such process and process for ejecting and projecting liquid droplets
EP1245396A3 (en) * 2001-03-28 2004-02-04 Canon Kabushiki Kaisha Process for forming image with liquid droplets, image forming apparatus utilizing such process and process for ejecting and projecting liquid droplets
US7044592B2 (en) 2001-03-28 2006-05-16 Canon Kabushiki Kaisha Process for forming image with liquid droplets, image forming apparatus utilizing such process and process for ejecting and projecting liquid droplets

Also Published As

Publication number Publication date Type
JP980669C (en) grant
DE2456597A1 (en) 1975-06-05 application
DE2456597B2 (en) 1976-08-12 application
JPS5087240A (en) 1975-07-14 application
GB1455674A (en) 1976-11-17 application
FR2252924A1 (en) 1975-06-27 application
JPS5413974B2 (en) 1979-06-04 grant
FR2252924B1 (en) 1976-10-22 grant

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